When you run rake db:create and get this error message

Couldn't create database for {"encoding"=>"utf8", "username"=>"root", "adapter"=>"mysql", "database"=>"project_development", "password"=>"topsecret"}, charset: utf8, collation: utf8_unicode_ci (if you set the charset manually, make sure you have a matching collation)

make sure the user you have specified (root/topsecret) in your database.yml has access to MySQL. You can check this by running mysql -uroot -p.

Most likely you run rake and your code is causing an exception which is not the one shown in your terminal.

Rails tries to catch this exception and clean up constants but -- while it's still booting up -- fails on this which causes another exception:

rake aborted!
cannot remove Object::ClassMethods

Running rake with the --trace parameter will give you no love; the backtrace is useless in most cases.

Try these approaches:

First: Check if there is a helpful error message

• Ha...

When installing your first formula, Homebrew may complain about not being able to access certain directories. The easiest solution to this is:

chown <username> /usr/local/Cellar /usr/local/share # create these directories if they do not exist

Then sudo brew install abc and you're going.

When your Solr seems to be started properly (a process is running with the correct data directory) but never responds properly and replies (via the API or web interface) with...
404 "Not Found"

... check if Solr's log directory is actually writable for the user running it.

When you put a Rake task into lib/tasks, but running it fails with...

Don't know how to build task name:of:task

... does your Rake task's filename end in .rb? It needs to end in .rake instead.

whatsmydns.net is an online service that allows you to instantly perform a DNS lookup to check a hostnames current IP Address and other DNS information against a selection of random name servers around the world. This is especially useful to check the current state of DNS propagation after making changes to your domains zones.

cURL makes a web request and shows you the response body.

You can redirect the response body to /dev/null just like for many other programs. But if you do that, cURL will display some short information about the request you are making:

$ curl http://www.example.com/ > /dev/null
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100 30865  100 30865    0     0   4793      0  0:00:06  0:00:06 --:--:-- 10199

If you wan...

Consider you have a website vhost listening to www.example.com, redirecting all incoming requests that do not talk about the configured hostname (this is often used to redirect users to http://www.example.com when entering only http://example.com/).

If you want to make a request to that site's web server without actually talking to www.example.com (e.g. because this is a load balancer's address but you want to access one specific machine), you cannot just request machine1.example.com or localhost as the above vhost will redirect...

ExecJS lets you run JavaScript code from Ruby. It automatically picks the best runtime available to evaluate your JavaScript program, then returns the result to you as a Ruby object.

We forked craken today and fixed one of the issues we had with new (>0.8.7) rake versions.

The craken:install rake task raised a "can't convert Hash into String" error e.g. while deploying with Capistrano.

https://github.com/makandra/craken

If you using gpg for your encrypted backup and it fails after you put it in crontab make sure you have the "--no-tty" option enabled for gpg.

Otherwise you get this error: "cannot open /dev/tty: No such device or address" and the backup size is 0 byte.

If your application raises an error like ...
Couldn't connect to the Solr server at http://127.0.0.1:8983/solr. 500 "Lock_obtain_timed_out_SimpleFSLock(...)"

... and if your jetty.request.log contains entries such as ...
127.0.0.1 - - [13/09/2011:12:42:23 +0000] "POST /solr/update HTTP/1.1" 500 4412
127.0.0.1 - - [13/09/2011:13:37:03 +0000] "POST /solr/update HTTP/1.1" 500 4309

... you probably have a lucene-...-write.lock file lying around in your Solr data directory that is not being cleaned up properly. This causes...

Random list of useful git commands for advanced users. I found some of them useful.

You can use fold:

fold -sw 60

You can now paste your texts. fold will echo them back, word-wrapped after 60 columns. Exit with Ctrl+C or Ctrl+D.

You can also use files for input and output:

fold -sw 60 input.txt > output.txt

In order to open a Nautilus window in your terminal's working directory, you can say:

nautilus .

When you drag a file from a Nautilus window into a terminal window, the file's path will be pasted into the terminal. This also works with multiple files.

The state_machine gem comes with a rake task that lets you generate PNG graphs from any model using state_machine.

Install the required dependencies like this:

sudo apt-get install graphviz
sudo gem install ruby-graphviz

You can now generate a graph like this:

rake state_machine:draw CLASS=ModelUsingStateMachine

Replace ModelUsingStateMachine with the name of your model class.

If it the raketask does not exist for you, add to Rakefile (in your pr...

If you get an error "Adress already in use" with autossh check with lsof or netstat if something already listen on the Ports you want to use.

There are three Ports you have to look at. If your Command look like this:

/usr/local/bin/autossh -f -M 5100 -g -N -C -L 8080:127.0.0.1:80 example.com -i ~/.ssh/id_rsa -l user

The following three ports need to be available:

1. 8080: The Port you want the tunnel to listen
2. 5100: The Autossh Monitoring Port
3. 5101: Autossh also uses the Monitoring Port +1

class Errormaster
  CoffeeIsOut = Class.new(StandardError)
  
  # is prettier than
  class CoffeeIsOut < StandardError; end
end

Reference such an error class with Errormaster::CoffeeIsOut.

Whenever Firefox updates, all your Cucumber features that use Selenium break. This is annoying.

In order to remedy this, version 0.5.0 of our geordi gem comes with a script that helps you create an unchanging version of Firefox for your Selenium tests. In particular, this new copy of Firefox will have the following properties:

• It won't update itself with a newer version
• It can co-exist with your regular Firefox installation (which you can update at will)
• It will use a profile separate from the one...

If you have different users for different servers, don't use set :user. Encode the username into the server definition instead:

server "username@servername.tld", :app, :web, :cron, :db, :primary => true

You can create a Regexp object from existing Regexp objects by using the interpolation syntax you know from strings:

re1 = /x/
re2 = /a#{re1}b/
'aaxbb' =~ re2 # => 1

Note

If your regular expression contains backreferences like \1, they may no longer refer to the correct capture group after concatentation.

Selenium does not speak SSL because it uses WEBrick that doesn't. When you use Selenium for Cucumber scenarios that visit pages with SSL, they will fail.

To turn off SSL only for scenarios that are executed on WEBrick, put this method into your application controller.

def ensure_proper_protocol
  request.headers['SERVER_SOFTWARE'].andand.include?('WEBrick') || super
end

Observed on Rails 2.3 and machinist 1.0.6

Like the title says, when you define the method empty? like in the following example, you may not longer use collection.make.

class Book

  has_many :pages

  def empty?
    pages.empty?
  end

end

Assuming

b1 = Book.find(1)
b2 = Book.find(2)

instead of expected

b1.pages.make #=> #<Page id: 1, book_id: 1>
b2.pages.make #=> #<Page id: 2, book_id: 2>

you'll get

b1.pages.make #=> #<Page id: 1, book_id: 3>
b2.pages.make #=> #<Page id: 2,...